Cyanine7.5 carboxylic acid chloride, a dye derivative of Cyanine 7.5 (Cy7.5) featuring carboxylic acid functional groups, is a near-infrared fluorescent dye used primarily in biomedical research for applications like biomarkers and cell imaging. It can covalently bind to biological molecules (especially antibodies, proteins, etc.) to monitor their location and dynamic changes in biological samples.